Pumps capable of use as heart pumps

ABSTRACT

The disclosure is of pumps which are capable of use as heart pumps, that is, for pumping blood in connection with the maintenance of the life function in a human or animal body to replace one or more pumping functions of the heart.

BACKGROUND OF THE INVENTION Field of the invention

The field of the invention is the field relating to apparatus forpumping blood of a living person, or of a living animal, to replace oneor more pumping functions of the human or animal heart in case ofdisability thereof. The heart replacement may be partial or complete.While the pumps provided according to the invention are providedprincipally for pumping blood, it will be apparent that the pumps may beemployed in other instances for pumping other materials. The pumpingequipment provided by the invention has rotating fluid accelerators orrotators. The pumps are adapted for pumping of blood and other delicatefluid materials without any pronounced physical effect on the blood orother fluid being pumped. The pumps do not impose sudden pressurechanges, impacts, rapid changes in direction of flow, in order toprevent injury to or destruction of the pumped material and itscomponents.

Description of the prior art

In the prior art, artificial heart pumps heretofore employed have beenof the positive displacement type. Because of the relatively delicatenature and structure of blood, it has been found that use of centrifugalpumps invariably results in physical disruption of the blood and atleast some of its components. Although it has been shown that apulsating movement of blood through the body is not necessary to sustainlife, the prior art has not afforded a solution to the problems involvedin utilization of centrifugal pumps for pumping blood, since at leastpartial destruction of the blood has always resulted when centrifugalpumps were used. This invention solves these problems, by providingrotative pumping means for pumping blood, without any significantdestruction of the blood and its components resulting from the pumping.

SUMMARY OF THE INVENTION

The invention is of rotative pumps which are suitable for use in primaryblood for circulation through the body passages, veins, arteries, etc.,of a living person or animal. The pumps are adaptable for use disposedwithin a body cavity, as replacements for either or both of the pumpingfunctions of the heart. The pumps herein provided may also be used forpumping blood externally of the body. The pumps are adapted to pumpwithout producing severe pressure changes, physical impacts, and thelike, so that none of the blood components is subjected to treatmentwhich will destroy it for use. The pumps do not require the use ofvalves, such as those of the heart, but valves may be provided ifdesired.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional view of one preferred form of pump accordingto the invention.

FIG. 2 is a partial cross sectional view showing a modification of thepump of FIG. 1.

FIG. 3 is a cross sectional view of a three-stage pump, according to theinvention.

FIG. 4 is a cross sectional view of a modified form of pump according tothe invention.

FIG. 5 is a partial cross sectional view taken at line 5--5 of FIG. 4.

FIGS. 6-8, 8A, and 9-12 show different forms of fluid accelerators orrotators which may be employed in pumps according to the invention; FIG.9, in addition, shows a built-in drive motor for the accelerator orrotator.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Blood is a complex and delicate fluid. It is essentially made up ofplasma, a pale yellow liquid containing microscopic materials includingthe red corpuscles (erythrocytes), white corpuscles (leukocytes), andplatelets (thrombocytes). These and the other constituents of blood, aswell as the nature of suspension of these materials in blood, are fairlyreadily affected by the manner in which blood is physically handled ortreated. Blood subjected to mechanical shear, to impact, todepressurization, or the like, may be seriously damaged. The balancebetween the blood constituents may be affected. Commencement ofdeterioration may result from physical mishandling of blood. Blood whichhas been damaged may be unfit for use.

The heart pumps blood through the body in a circulating, cyclic,fashion. The blood passes repeatedly through the heart. A pump forreplacing one or more pumping functions of the heart should therefore becapable of repeatedly pumping the same blood, time and time again,without damaging the blood, at least not more than to the extent wherethe body can function to repair or replace the blood components andeliminate damaged and waste materials therefrom.

Blood also contains dissolved and chemically combined gases, which maybe seriously affected by improper physical handling of the blood. Ithas, for example, been established that subjecting blood to negative orsubatmospheric pressures of, say, minus 300 millimeters of mercury, isdetrimental, even when the reduced pressures are only temporary.

The blood pressure is the pressure of the blood on the walls of thearteries, and is dependent on the energy of the heart action, theelasticity of the walls of the arteries, the peripheral resistance inthe capillaries, and the volume and viscosity of the blood. The maximumpressure occurs at the time of the systole of the left ventricle of theheart and is termed maximum or systolic pressure. The normal systolicpressure may be from about 80 millimeters of mercury (mm. Hg) to about150 mm. Hg. the pressure ordinarily increasing with increasing age.Pressures somewhat outside this range are not uncommon. The minimumpressure is felt at the diastole of the ventricle and is termed minimumor diastrolic pressure. The diastolic pressure is usually about 30 to 50mm. Hg lower than the systolic pressure.

The preferred embodiments of the invention shown and described have incommon that the blood or other delicate fluid is handled gently, withoutshear, shock, vibration, impact, severe pressure or temperature change,or any other condition or treatment which would unduly damage the bloodor other fluid. Essentially non-turbulent flow is maintained through thepumps, and the pumped fluid is accelerated gradually and smoothly.

The pumping action obtained may be described as radially increasingpressure gradient pumping, or in some cases more specifically as forcedvortex radially increasing pressure gradient pumping. In centrifugalpumps, the fluid acted on by the vanes of the impeller is positivelydriven or thrown outwardly (radially) by the vane rotation. The fluid asit moves from the vanes to the ring-shaped volute space beyond the tipsof the vanes is reduced in velocity, and as the velocity decreases thepressure increases according to Bernoulli's theorum. On the other hand,in the pumps provided according to this invention, the pumped fluid isnot driven or thrust outwardly but instead is accelerated to circulatein the pumping chamber at increasing speeds as it moves farther andfarther from the center. As the outer periphery of the accelerator orrotator, the speed of the fluid is maximum.

The action of the fluid in the pumps may be clarified by analogy to aglass of water turning about its vertical axis without sideways motionor wobble. Because of its contact with the sides and the inherentpotential shear force of the water in the glass, the water will rotate,in the form of a forced vortex, without much clip or shear betweenradially adjacent particles of water, and the water radialy away fromthe center of rotation will be moving faster than water nearer thecenter. If water is introduced through a tube at the axis of the glassand water is removed through one or more holes through the side of theglass, water will be pumped by the rotation of the glass. In the pumpsafforded by this invention, while rotators are provided, in a number ofdifferent forms, the rotators are designed such that they act toincrease the swirling speed of the liquid passing through the pump, butdo not act to drive or throw the liquid toward the periphery or voluteof the pump chamber, but instead only increase the rotational speed ofthe liquid. As the rotative speed of the liquid is increased, itachieves a higher "orbit" about the center of the accelerator and movestoward the periphery of the chamber.

Referring first to the apparatus shown in FIG. 1 of the drawings, ahousing 15 has parallel spaced circular walls 16, 17. At the center ofwall 16, an offset chamber 19 is formed which terminates outwardly in aninlet passage 20. Wall 17 has at its periphery circular formations 22,23 joined by peripheral wall 24 between which is formed a peripheralring-shaped chamber 27. Formation 22 is internally shaped to provide aflow-direction flaring surface 28. Wall 16 is connected to formation 22by a plurality of circularly spaced screws 29.

A rotative circular vane 31, forming one side of the accelerator orrotator 30, has at one side a flared inlet formation 32 which extendsinto chamber 19 and is sealed to the wall of chamber 19 by O-ring 34 andwhich rotates in bearing 35 disposed within chamber 19. The interiorwall of inlet 32 is flush with the wall inlet 20. An O-ring 36 aroundthe periphery of flat vane or disc 31 seals with the inner side offormation 22. The inner side of vane 31 is flush with the beginning ofcurved surface 28 so that fluid flowing through the pump introducedthrough entrance 20 flows smoothly from entrance 20 to entrance passage32, through the pump chamber, and smoothly past the intersection of theperiphery of vane 31 and surface 28.

Vane 31 is connected to a second rotating vane 38, forming the otherside of accelerator or rotator 30, which is concentric and parallel tovane 31, by circularly spaced pins or rods 39. Vane 38 has O-ring 40about its periphery to seal with the inner side of formation 23. Anoutlet passage 41 is provided at one side of wall member 17, it beingpossible to provide any number of such outlets circularly spaced aboutthe pump as is desired. Wall 17 has at its center a central passage 43containing bearing 44 which is in contact with rotating shaft 45connected to, or forms a part of, vane 38. Vane 38 has at the center ofits inner side the rounded projection 38a, which guides incoming fluidto flow smoothly along the vanes.

The pump shown in FIG. 1 operates in the following manner: The fluid tobe pumped flows inwardly through passage 20 into passage 32 to the spacebetween rotating accelerator vanes 31, 38. Shaft 45 is driven rotativelyby means not shown, and vanes 31, 38 rotate together (in eitherdirection) because of their connection at pins or rods 39. The pumpoperates on a forced vortex principal, there being no impeller surfacesin the pump for impelling blood or other fluid material being pumpedradially outwardly toward the periphery of the pump chamber. A forcedvortex pump operates on the principal that a rotating chamber causesrotation of its contents, with creation of a vortex, so that a body ofcirculating fluid is maintained within the pump chamber by rotation ofthe vanes 31, 38 at opposite sides of the chamber, whereby therotational speed of liquid in the pump is increased from the center tothe periphery of the chamber of the pump. The liquid is withdrawnthrough the outlet 41, and as has been stated before, a plurality ofoutlets 41 may be provided if desired.

It will be seen that the blood or other fluid passing through the pumpis not submitted to any substantial agitation by the rotation of thevanes, or by any other portion of the pump apparatus. There are nosudden changes in direction of the flow through the pump, all jointsbetween surfaces being smooth and all surfaces over which the fluidflows being smooth.

Referring now to FIG. 2 of the drawings, there is shown a portion of apump identical to that shown in FIG. 1 except that the flow outlet is ofmodified form. The outlet 41a from the pump chamber is shown to bedisposed radially from the pump chamber instead of parallel to the pumpaxis as in FIG. 1. The wall elements 16a, 17a are like those shown inFIG. 1 except that the curved surface 28 is omitted at the interior offormation 22a and the peripheral chamber 27a is of rectangular crosssection. The vanes 31, 38 are as shown in FIG. 1, as is also theremainder of the pump, only the peripheral portions of the pump elementsbeing modified as shown. The operation of the pump in FIG. 2 is the sameas that of the pump of FIG. 1, except that the pumped fluid exists fromthe pump radially instead of in line with the pump inlet. Plural outlets41a may be provided if desired.

Referring now to FIG. 3 of the drawings, there is shown a pump 50 havingthree serially disposed pumping stages, whereby the pressure of blood(or other fluid) pumped may be higher than the pressure obtained in asingle stage of pumping, such as by the pumps shown in FIGS. 1 and 2.The pump housing is made up of housing elements 51, 52, 53 and 54. Thehousing elements are joined at peripheral bolt flanges 55-56, 57-58,59-60, the bolts not being shown.

The pump of FIG. 3 has three pumping chambers 61a, 61b, 61c, and tworeturn chambers 62a, 62b through which the fluid pumped by the first twopumping stages is returned to the center of the pump for the nextpumping stage.

The rotator or accelerator 63 in pumping chamber 61a includes a flatcircuit vane 64, having peripheral flange 65, and sealed to the housingfor rotation therein by O-ring seals 66, 67, and a flat circular vane 68spaced from vane 64 and supported by plural circularly spaced pins orrods 69, and mounted at its center on shaft 70.

The return chamber 62a is formed between circular plate 71 and housingwall 52a, plate 71 being supported by wall 52a through plural circularlyspaced pins 72, and sealed to the periphery of vane 68 by O-ring 73.Vane 68 and plate 71 are of the same diameter. Shaft 70 is disposed forrotation through plate 71 at O-ring seal 74.

The rotator or accelerator 75 in pumping chamber 61b includes vanes 76,77 which are identical with vanes 64, 68, respectively, except thatshaft 70 extends completely through vane 77 as shown. The seals 66, 67and rods 69 are provided as before. Rotator 75 differs from rotator 63,however, in that a plurality of relatively thin flat plates or sheets78a-78c are spaced parallelly between the facing sides of vanes 76, 77within the pumping chamber. Plates 78a-78c are circular and may be ofthe same or different diameters. They are supported at perforationstherethrough by the pins 69 extending between vanes 76, 77. Any numberof these plates may be provided, so long as the spacings therebetwen donot become small. The spacings between the adjacent vanes and platesshould not be less than about 1/4 inch. If the vanes and plates arespaced more closely, the shear stresses imposed on the blood or otherfluid become excessive, with resulting trauma of blood and harmfulphysical effects in the case of other fluids. In Transactions of theASME, July 1963, page 205, it is stated in the second complete paragraphof column 2, that in pumps therein termed "shear-force pumps," that "Dueto the necessity for very close spacing of the shear surfaces, the pump"(ed) "fluid must be essentially free of suspensions." It should be madeclear at this point that the utilization of very close spacings is notcontemplated by this invention, so that the invention is distinguishedover the apparatus described in the aforementioned article, and also isdistinguished over apparatus of the type or kind proposed in Patent No.1,061,206 to Tesla. In such apparatus, the emphasis is on very highrotational velocities and very close spacings, which make them unfit foruse insofar as the contemplation of this invention is concerned.According to this invention, the emphasis is on gentle, non-turbulenthandling of the pumped fluid, as is illustrated by the aforementionedrotating glass of water with nothing to rotationally accelerate thewater but the smooth side of the glass. Yet, the water after a timerotates with the glass and continues the rotation as long as the glasscontinues to rotate.

Return chamber 62b is identical with return chamber 62a, and includeselements 71a, 53a, 72a, 73a, 74a, respectively identical with elements,71, 52a, 72, 73, 74 heretofore described.

The rotator or accelerator 80 is made up of vanes 81, 82 which arerespectively identical in form with vanes 64, 76 and 68, 77. The rods 69are omitted, and the vanes 81, 82 are connected by plural vanes 83,radially disposed and arcuately spaced. The vanes 83 may be flat asshown, or may be curved end-to-end and twisted like the vanes shown inFIG. 9. Any suitable number of vanes 83 may be provided. Each vane 83extends from near the axis of the pumping chamber to terminate the linewith the inner face of vane 82, as shown.

Within housing element 54, there is a ring-shaped chamber 85 disposedbetween circular walls 86, 87, 88, walls 87, 88 being aligned with thesides of the annular opening between vanes 81, 82. Outflow opening 89 isprovided through wall 88, and plural such openings may be provided ifdesired.

Shaft 70 is rotated by means not shown to rotate the vanes of the threerotators.

The flow inlet to the pump is provided through nipple 51a and circularopening 64a aligned flushly therewith.

It will be realized that pumps may be supplied according to theinvention with any number of pumping stages, and may include individualpumping stages of any of the types mentioned herein in any combination.

Referring now to FIGS. 4 and 5 of the drawings, there is shown a pump110 having a housing made up of members 112, 113 identical with thecorresponding housing members of FIG. 2 except that bearings 135 is in adifferent disposition than bearing 35 (see FIG. 1). Elements of FIGS.1-2 which are the same as indicated by the same reference numerals inFIGS. 4-5. The accelerator 119 includes a flat circular vane 120 and asecond flat circular vane 121. The vanes 120, 121 are connected by thefull-radius curved vanes 125, and the shorter curved vanes 126, 127, and128. As best shown in FIG. 5 of the drawings, the vanes 125 extend fromthe center of the accelerator to its periphery, the vanes 126 extendfrom a point spaced from the center of the accelerator to its periphery,and the vanes 127, 128 extend from about the centers of vanes 126 to theperiphery of the accelerator. Four of each type of vanes are shown inthe drawing.

The objective of this configuration of the vanes is that the impetus ofthe vanes in thrusting the pumped fluid outwardly is minimal, only fourof the sixteen vanes acting on the blood, or other fluid, as it emergesfrom the entrance into the pump chamber, and, as the blood progressesthrough the blood chamber, from its center toward the periphery,additional vanes take action to move the blood in its spiral motion,with increasing velocity, toward the periphery of the pumping chamber.

The rotator 119 has a flared entrance 130 which merges smoothly into theface of vane web 120. The interior of entrance 130 blends smoothly withthe interior of entrance 20 which is formed in the offset space 19 at aside of the housing.

At the opposite side of the housing, wall 113 has at one side acylindrical formation 134 through which rotative shaft 135 is disposedwithin bearing 136, and O-ring seal 137 is disposed about the outerperiphery of vane 121 to seal between the vane and housing.

The housing has at one side the radially disposed outlet 138 havingoutflow passage 139 therethrough. Any number of similar outlets may beprovided.

A ring shaped screen 140 is disposed around the ring shaped space 27a ofthe apparatus of FIGS. 4-5, the screen dividing the space into inner andouter annular portions. The screen may be omitted. Any porous orperforate divider may be substituted for the screen, e.g. a plate havingone or more openings, spaced bars, etc. The screen serves to create twodistinct annular flow zones within space 27a, an inner zone in which thefluid moves circularly as accelerated by the rotator, and an outer zonereached by the fluid by outflow through the screen, over its completecircular length, the fluid flow through the screen reducing its circularvelocity. Thus, the outer zone is a zone of slower velocity from whichthe fluid moves in the outlet 139, whereby eddy currents and turbulenceat the outlet is reduced.

Referring now to FIGS. 6-12, there are shown a number of forms ofrotators or accelerators which may be used in the pumps, these beingshown more or less schematically. The rotators 141, 142 shown in FIGS. 6and 7 are similar, each having a pair of curved blades or vanes 150-151and 153-154, respectively. The views shown are cross sections taken atright angles to the axis of rotation of each rotator, and the rotatorshown in FIG. 6 has a flat side plate or vane 155 which is circular, andsimilarly the accelerator shown in FIG. 7 has a side vane or plate 156,also circular. In most cases there will be another plate 155 or 156 atthe other, or near, side of the vanes. The rotators, therefore, areenclosed at their sides by these plates. The rotator of FIG. 6 hascentral openings 158 where the liquid to be pumped enters, and a pair offlow passageways between the vanes indicated by reference numerals 159,160 which are of constant cross section from the center to the peripheryof the rotator. Fluid passing through this rotator does not haveopportunity for volume expansion, as the flow passages, through which itmoves are of constant size from their beginning to their end. Therotator of FIG. 7, on the other hand, has the pair of flow passages 162,163 extending from the center to the outside of the rotator whichincrease in cross section from their central entrance to theirperipheral outlet ends.

The rotator shown in FIG. 8 consists of a hollow, drum-like, body 165,having a cylindrical tube 166 between central openings at each of itssides, and having a curved peripheral wall 167. The tube 166 and wall167 have plural openings 168, 169, respectively, any suitable numbersand spacings of these being provided, four of each being showncircularly equally spaced. Fluid enters through tube 166 and flows intothe drum through openings 168. The drum is rotated and the fluid thereinis caused to rotate, the rotator giving the fluid circular motion but nooutward radial motion. Centrifugal force resulting from circular motionof the fluid, however, causes the motion of the fluid to be spiralinstead of circular, so that the fluid after moving spirally through thespace within the drum flows outwardly through the openings 169 into thepumping chamber space annularly around the rotator, from which the fluidexits through one or more outflow passages of any suitable form. A pairof O-ring seals 170, 171 disposed in suitable grooves around theopposite edges of the body 165 seal between the rotator and the pumphousing in the manner shown in other drawing figures.

In FIG. 8A, a rotator is shown which is a modification of that shown inFIG. 8, and to which the description of FIG. 8 applies to the elementsindicated by the reference numerals of FIG. 8, the modification residingin the addition of the tubes 173, each of which extends between one ofthe inner holes 168 and one of the outer holes 169 at the same side ofthe rotator. The tubes 173 may be straight and radial as shown in thedrawing, or may be curved or angular, by proper positions of the holes168, 169 and shaping of the tubes. In this rotator, the fluid would passfrom tube 166 through tubes 173 to exit at the periphery, upon rotationof the rotator.

Referring now to FIG. 9 of the drawings, a rotator 175 is shown whichhas a plate or disc 176 at each of its sides which may be identical orof different form or size, only one being shown in the drawing, andbetween which there are provided the equally circularly spaced curvedblades 177a-177h, each curved from its inner end to its outer end asshown and each having a twist throughout its length similar to the twistof a propeller. The blades or vanes, may extend beyond the outer edgesof the discs 176. Each blade 177a-177h carries a winding 178, which iscovered by an impervious layer or membrane 179. The blade windings areconnected to contact elements of a commutator 180. The surrounding pumphousing is provided with the circularly spaced magnets or coils 181,which are separated from the pumping chamber by an impervious layer ormembrane 182. The commutator rotates with the rotator in the usualmanner of an electric motor. The rotator windings and housing magnets orcoils constitute an internal electric motor for driving the rotator topump fluid. The electric motor thus provided may be of any of the knowntypes, AC or DC, with or without commutation powered by electricalconductors leading thereto from any suitable AC power source or from abattery, located either internally or externally of the body. Theconductors may be disposed through the outer body wall from the exteriorof the body, installed surgically. The power source may includecapacitance connections, across the body wall, with both of its platesbeneath the skin, or with one plate interior of the skin and the otherexterior of the skin. A battery power source may be disposed within thebody, and replaced periodically by surgery, or recharged inductivelyfrom the exterior of the body. Batteries capable of operation forperiods in excess of one year are available, so that surgery for theirreplacement would need to be done either annually or at longerintervals.

While the self contained drive motor is herein shown and described inconnection with the rotator of FIG. 9, it will be understood that it maybe provided in conjunction with all of the other forms of rotatorsdisclosed herein.

The descriptions concerning power supplies to the motor of FIG. 9 will,of course, relate also to power sources for motors connected to pumpshafts external of the pump housings.

Referring now to FIG. 10 there is shown a rotator in the form of a plate185, the peripheral edge 186 of which is of corrugated formation. Theradial corrugations each extend narrowingly to the center opening 187 ofthe plate. The curved corrugation surfaces are adapted for accelerationof fluid circularly as the rotator is rotated, in either direction,about its center. This form of plate may be used alone as a rotator, orplurality as the flat plates of the second stage of the pump shown inFIG. 3. Similarly, the flat vane surfaces, such as in FIGS. 1 and 2, maybe corrugated to enhance their accelerative purpose. Rotators of thisform present only smooth surfaces to the blood or other fluid beingpumped.

In FIG. 11, there is shown an accelerator or rotator having spacedparallel circular plates 190, 191 at the inner side of each of which areprovided circularly spaced radial vanes 192 and 193. The vanes 192, 193are staggered as shown, the vanes of each plate 190-191 beingalternately disposed and extending only partway toward the oppositeplate 190 or 191.

Referring now to FIG. 12 of the drawings, the rotator therein shown hasa pair of opposite sides vanes or plates 197, only one being shown,between which are disposed a plurality of circularly spaced curved vanes198. These vanes are of a shape, when rotated in the direction of arrow202, serve to pick up blood from the entrance 203 to move it into therotative path of the vanes, and then the concave curves of the vanes actto accelerate the fluid circularly while restraining somewhat outflowtoward the periphery of the rotator, and at the same time lengtheningthe flow paths of the fluid from the center to the periphery of therotator.

In each of the pumps shown in FIGS. 1-5, and pumps wherein use is madeof rotators (or accelerators) of the different forms shown in FIGS.6-12, it will be noted that the rotators are designed to avoidturbulence and to avoid rapid pressuring and depressuring of the bloodor other fluid being pumped, and also to avoid any physical grinding orabrasive action upon the fluid. As has been made clear, these rotatordesigns are made in this manner in order that blood or other delicateliquids or gases being pumped, some containing solids in suspension,will not suffer detriment and will not be destroyed by the pumpingoperation.

In contrast to centrifugal pumps, the revolutions per minute of therotators employed with the pumps herein shown and described are keptminimal. The several rotator designs presented are each of a formadapted to progressively increase the circular fluid velocities as therotator turns and as the fluid advances toward the periphery of therotator. In each pump presented, an annular fluid circulation space isprovided, which is entirely unobstructed and regular so that fluid cancirculate therein without turbulence or baffle effects.

As hereinbefore indicated, pumps may be made according to the inventionincorporating features from one or more of the preferred embodimentsshown and described herein, any particular feature not being confined touse only with the other features in connection with which it is hereinshown and described.

The pumps and their parts may be constructed of any materials compatiblewith their intended use, including metals, mineral materials, plastics,rubbers, wood, or other suitable materials. When blood is to be pumped,consideration must be given to biological compatibility so that traumato the blood will not result. Teflon has been successfully used incontact with blood, without traumatic effects, and may be used inconstruction of the pumps for blood pumping adaptations. Non-corrosivemetals and alloys may be used in the pumps where required.

In the embodiment of FIG. 9, Teflon may be used for the membranes 179,182 covering the windings of the electric motor structures.

The housings and rotators may be constructed of suitable material sothat the housing may be rigid, semi-rigid, or elastic in whole or inpart. The non-rigid constructions can be used for imparting pulseconfigurations to blood in heart simulation pumps.

While the rotators shown herein may in some cases perform better whenrotated in one direction, it should be understood that they may berotated in either direction, i.e. reversed, without other modificationof the pumps. Each of the rotators presents surfaces to the fluid beingpumped, to cause accelerating circular fluid motion in the pumpingchamber. In some cases, the surfaces are parallel to the fluid flow; inother cases parallel and non-parallel surfaces are provided. Each ofthese surfaces, of whatever form, will accelerate the fluid regardlessof the direction of rotation of the rotator. Each rotator should berotated at a speed such that essentially no fluid turbulence occurs, anddifferences in the rotator designs affects the maximum speed at which aparticular rotator may be rotated. The physical and flow properties ofthe fluid pumped will, of course, also affect the maximum speeds ofrotation at which the rotators may be operated without turbulence andother objectionable effects, such as cavitation, vapor binding, and thelike. It is, therefore, not possible to set forth exact rotational speedranges for the rotators. But, the speeds of rotation will always belower and will usually be substantially lower than those of centrifugalpumps and blowers, wherein turbulence always occurs at the impellersthrust the fluid radially outwardly against the periphery of the pumpingchamber, and those of the aforementioned multiple disc pumps andcompressors. To the end of achieving reduced rotator speeds, pumpsprovided according to this invention may be of larger size than otherpumps, for the same pumping capacity. As internally placed heart pumps,the pumps may be as large as five inches in diameter, and, with removalof a lung, even larger.

According to the precepts of this invention, the forms of the rotatorsmay vary considerably. For example, the rotators may be constructedentirely or partly of porous or perforate materials, i.e. the vanes ofthe rotator which accelerate the fluid circularly may be made of screen,of perforate plates or sheets, of spaced rods, or the like, and willstill ably perform their fluid accelerating function. Rotators may be ofaxially extended form, so that the fluid is accelerated axially oraxially and radially. Designs of this nature would extend the flowpathfrom inlet to outlet so that acceleration would be at a slower rate. Inthe rotator of FIG. 7, the vanes could be made to become closertogether, instead of farther apart, toward the periphery of the rotator.In each of the pumps shown and/or described, one or more tangentialoutlets could be provided, disposed in the direction of fluid flowinside the peripheral wall of the pump. In multi-stage pumps, such asthat shown in FIG. 3, the several rotators, which may be alike orunlike, may be driven at different rotational speeds. The axes ofmulti-stage rotators may be offset and in other positions out ofalignment.

While preferred embodiments of apparatus according to the invention havebeen shown and described, many modifications thereof may be made by aperson skilled in the art without departing from the spirit of theinvention, and it is intended to protect by Letters Patent all forms ofthe invention falling within the scope of the following claims:

What is claimed is:
 1. Pumping apparatus for use in pumping fluidssusceptible to damage from turbulence and shock, comprising housingmeans having central fluid inlet means and peripheral fluid outletmeans, rotator means disposed for rotation within said housing means andhaving surface means for accelerating fluid in substantially circularmotion without said housing means as said fluid flows between said inletmeans and said outlet means, means for sealing between said housing androtator centrally about said inlet means and around the periphery ofsaid rotator means, said inlet means including port means through saidrotator means at the rotative axis thereof opening toward the peripheryof said housing means, said surface means of said rotator meanscomprising plural parallel surfaces substantially each parallel to theplanes of circular movement of said fluid passing through said housingmeans from said inlet means to said outlet means, said plural parallelsurfaces being spaced at least one-fourth inch apart, said rotator meansbeing adapted to rotate at a speed such that fluid passed thereto fromsaid inlet means is caused to rotate circularly at substantially thespeed of said rotator means, whereby turbulence and shock to said fluidin passing from said inlet means to said outlet means is avoided. 2.Pumping apparatus for use in pumping fluids susceptible to damage fromturbulence and shock, comprising housing means having central fluidinlet means and peripheral fluid outlet means, rotator means disposedfor rotation within said housing means and having surface means foraccelerating fluid in substantially circular motion within said housingmeans as said fluid flows between said inlet means and said outletmeans, means for sealing between said housing and rotator centrallyabout said inlet means and around the periphery of said rotator means,said inlet means including port means through said rotator means at therotative axis thereof opening toward the periphery of said housingmeans, said surface means of said rotator means including at least onesurface parallel to the planes of circular movement of said fluidpassing through said housing means from said inlet means to said outletmeans and at least one other surface angular to said one surface, saidrotator means being adapted to rotate at a speed such that fluid passedthereto from said inlet means is caused to rotate circularly atsubstantially the speed of said rotator means, whereby turbulence andshock to said fluid in passing from said inlet means to said outletmeans is avoided.
 3. The combination of claim 2, each said other surfacebeing curved between the center and periphery of said rotator means forelongating the paths of fluid flow therebetween.
 4. The combination ofclaim 2, said surface means including at least one circular band shapedsurface concentric with said rotator. .Iadd.
 5. Blood pumping apparatus,comprising:a. housing means defining a chamber; b. rotator meansdisposed for rotation within said chamber of said housing means andincluding at least two coaxial, spatially separated, smooth surfacedrotative vanes having axially spaced surfaces for accelerating bloodintroduced into the spatial separation between said vanes in asubstantially circularly outward direction; c. inlet means positionedwithin said housing means for introducing blood into the spatialseparation between said rotative vanes generally along the rotative axisthereof; d. outlet means positioned peripherally within said housingmeans for removing the outwardly accelerated blood; e. means forrotating said rotative vanes at a speed such that the blood introducedinto the spatial separation between said vanes is caused to rotatecircularly at substantially the speed of said spatially separated vanespreventing turbulence and shock to the blood as the blood movescircularly outward between said inlet means and said outlet means; andf. said rotative vanes being spaced apart a sufficient distance inrelationship to the area of their surfaces in contact with the blood,said distance being on the order of one-fourth inch and greater, tominimize shear stresses imposed on the blood by frictional contact withthe vane surfaces while maintaining a body of blood circulating withinthe chamber to provide a forced vortex radially increasing pressuregradient pumping action. .Iaddend..Iadd.
 6. Pumping apparatus for use inpumping fluids susceptible to damage from turbulence and shock,comprising: a. housing means defining a generally cylindrical chamber;b. rotator means including at least two smooth surfaced circularaccelerator vanes disposed for simultaneous rotation within saidcylindrical chamber and positioned in a spatially separated relationshipfor accelerating fluid introduced into said spatial separation in anessentially circularly outward direction, at least one of said circularaccelerator vanes defining a generally centrally positioned passagewaytherethrough, said surfaces being spaced at least one-fourth inch apart;c. fluid inlet means positioned within said housing means forintroducing fluid through said passageway in said accelerator vane intosaid spatial separation between said vanes generally along the rotativeaxis thereof; d. fluid outlet means positioned peripherally within saidhousing means for removing the outwardly accelerated fluid from saidcylindrical chamber; and e. means for rotating said accelerator vanes ata speed such that the fluid introduced into said spatial separationbetween said vanes is caused to rotate circularly at substantially thespeed of said vanes so as to prevent turbulence and shock to the fluidin passing circularly outward between said inlet means and said outletmeans. .Iaddend.